Many excellent reviews exist already focusing either
on the more general topic of X-ray spectroscopy, mainly of the ICM, or directly on metal abundances both observationally and theoretically [1]}, [2]}, [3]}, [4]}, [5]}, [6]}, [7]}, [8]}, [9]}, [10]} that ease our work which will then focus on the topics more directly related to the recent updates about metal abundances in galaxy groups. In this respect the only reviews of the topic are about the early history of the metal abundance measurements in the IGrM described in [11]} and a more recent update including the Chandra and XMM-Newton data can be found in [12]}. A comparison of the metal budget in groups compared to the one in clusters and elliptical galaxies has been discussed in [9]}.
